There is no way to have Toodledo default to a collaborator view. You could try Public shring which would give you a URL from which all your non-private Folders can be viewed, but that would only work if you only want you secretary to have read-only access and the view option are less extensive. So if you want your secretary to be able to edit tasks, or you are not comfortable with enabling public sharing, then this will have to be a feature request. I know there are plans to improve Toodledo's collaboration features, including the way shared Folders are viewed.